I. Technical Field
The present invention relates to detecting a specified object included in image data.
II. Description of the Related Art
Conventionally, imaging devices such as digital still cameras, video cameras, etc. have had the function of detecting a region within a captured image in which a specified object is photographed, and the control focus of the camera is based on the detection results.
An object detection method that detects the position of an object within a captured image has been proposed, the method being able to detect the positions of multiple objects with differing sizes within the image.
A proposed image processing device (object detection device) that uses this sort of object detection method searches for a region in which an object appears by performing matching processing (hereinafter referred to as “template matching processing”), using a template TP that reflects features of an object, on an original image G0 and a plurality of reduced images G1, G2, . . . , G7 with differing resolutions generated from the original image G0, as shown for example in FIG. 18 (see Japanese Patent Application Publication No. 2007-135115 and Japanese Patent Application Publication No. 2008-257321).
FIG. 19 is a block diagram showing the configuration of the object detection device recited in Japanese Patent Application Publication No. 2007-135115.
A face detection unit 1001, which forms part of the image processing device in Japanese Patent Application Publication No. 2007-135115, acquires an original image G0 from an image Random Access Memory (RAM) 1002 via a bus 1003, generates a plurality of reduced images G1, G2, . . . , G7 with differing reduction rates from the original image G0 via a resolution conversion unit 1015, and stores the reduced images in both an internal image memory 1021 and, via the bus 1003, in the image RAM 1002. A face detection core 1007 performs template matching processing on the reduced images G1, G2, . . . , G7 stored in the image memory 1021.
Furthermore, Japanese Patent Application Publication No. 2008-257321 discloses an example of a face detection device (object detection device) provided with a resolution conversion circuit that generates reduced image data by converting the resolution of original image data, and with a face detection circuit that detects a face by performing template matching processing on the reduced image data, wherein all of the reduced image data generated by the resolution conversion circuit is stored in an image memory provided externally to the resolution conversion circuit and the face detection circuit.